1. Field of the Invention
This invention relates to a method for the preparation of an alumina catalyst support, a catalyst comprising the support and hydrocarbon treating processes utilizing the catalyst.
2. Description of the Prior Art
It is known to extract calcined alumina which may have been formed into the desired shape with an acid to dissolve a portion of the alumina and, thereby, produce an alumina catalyst support substantially free of pores smaller than 70 Angstroms while having a pore volume substantially the same as that of the non-acid extracted alumina. See U.S. Pat. No. 3,038,865.
It is known to prepare active alumina agglomerates of high mechanical strength by treating pellets of alumina in an autoclave in an acidic medium at a temperature above 100.degree. C. for 1 to 20 hours, followed by drying the treated pellets and calcining the dried pellets. See U.S. Pat. No. 3,628,914.
A process for the manufacture of a pellet type of catalyst is known which comprises wet grinding a metal oxide, such as alumina, to obtain particles having a size less than 40 microns, and thereafter, molding the mass of particles into pellets at elevated pressures. See U.S. Pat. No. 2,921,033.
It is also known to increase the macroporosity of calcined alumina by treating the calcined alumina with certain organic acids, such as dicarboxylic acids. See U.S. Pat. No. 3,997,476.
A catalyst is also known having a total pore volume comprised of micropores and access channels, the latter being interstitially spaced throughout the structure of the micropores. The access channels having diameters between 100 and 1000 Angstroms constitute 10 to 40 percent of the total pore volume and the access channels having diameters greater than 1000 Angstroms constitute 10 to 40 percent of the pore volume while the remainder of the pore volume comprises 20 to 80 percent of micropores with diameters less than 100 Angstroms. See U.S. Pat. No. 3,630,888.
Hydroconversion in the presence of an ebullated catalytic macroporous microspheres smaller than 60 mesh and larger than 325 mesh (U.S. Standard), is known. See U.S. Pat. No. 3,622,500.
Pressures ranging from 5 to 20 tons per square inch to pelletize a mixture of catalyst constituents are known. Calcination can be conducted before or after pelleting. See U.S. Pat. No. 3,846,286.
It has now been found that a catalyst support prepared in accordance with the present invention will provide advantages that will become apparent in the ensuing description
By the term "hydrotreating" is intended herein the contacting of a hydrocarbon feed with a catalyst in the presence of hydrogen under selected conditions to remove heteroatoms such as sulfur, oxygen and metallic contaminants such as nickel, vanadium and iron from the feedstock and/or to saturate aromatic hydrocarbons and/or olefinic hydrocarbons in the feedstock and/or to hydrocrack the feedstock.
The term "hydroconversion" is used herein to designate a catalytic hydrotreating process conducted in the presence of hydrogen in which at least a portion of the heavy constituents of the hydrocarbonaceous feedstock is converted to lower boiling hydrocarbon products. Simultaneously, the concentration of nitrogenous compounds, sulfur compounds and metallic contaminants of the feedstock may be reduced.